为什么我的列表视图没有显示任何记录？ [英] why is my listview not showing any records?

问题描述

我正在使用下面的代码填充我的列表视图。 'count'整数值显示一些值，但listview保持为空。我做错了什么？

i am using the code below to populate my listview. the 'count' integer value shows some value but the listview remains empty. what am i doing wrong?

Public Sub populate_lvw()
       If con.State = ConnectionState.Open Then
           con.Close()
       End If

       lvw.Items.Clear()
       lvw.Scrollable = True
       ds.Clear()
       da.Dispose()

       str = "SELECT scholarship_id FROM Scholarships WHERE scholarship_category= '" & categoryCb.Text & "'"
       Dim cmd As SqlCommand = New SqlCommand(str, con)
       con.Open()
       Dim scholarship_id As Integer = CInt(cmd.ExecuteScalar())
       MsgBox(scholarship_id)

       Dim dr As SqlDataReader = Nothing
       cmd = New SqlCommand("Select * from Students where scholarship_id like @searchitem  order by student_slno", con)
       cmd.Parameters.AddWithValue("@searchitem", scholarship_id)
       dr = cmd.ExecuteReader

       Dim count As Integer = 0
       While dr.Read
           count = count + 1
       End While
       MsgBox(count)

       If dr.HasRows Then
           While dr.Read
               Dim li As New ListViewItem()
               li.Text = Convert.ToString(dr.Item("student_slno"))
               li.SubItems.Add(Convert.ToString(dr.Item("student_fullname")))
               ' li.SubItems.Add(Convert.ToString(dr.Item("student_dob")))
               li.SubItems.Add(CType(dr.Item("student_dob"), DateTime).ToShortDateString)
               li.SubItems.Add(Convert.ToString(dr.Item("student_branch")))
               li.SubItems.Add(Convert.ToString(dr.Item("student_scholarship")))
               li.SubItems.Add(Convert.ToString(dr.Item("student_accountno")))
               lvw.Items.Add(li)
           End While
       Else : MsgBox("Sorry, no records found!")
       End If
       dr.Close()
       con.Close()
   End Sub

推荐答案

检查Listview.View =详细信息，然后你需要在列集合中定义的至少一列。

Check if the Listview.View = Details, then you need at least one column defined in the columns collection.

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